Independent vehicle suspension systems are used to absorb road shocks and other vibrations and provide a smoother, more comfortable automobile ride. In suspension systems of this type, a stabilizer bar is normally incorporated to increase roll resistance and improve the steering to stability of the vehicle. Typically, the stabilizer bar is a torsion rod that extends transversely of the vehicle. It has an integral crank arm provided at each end. The rod is rotatably supported from the vehicle chassis adjacent each crank arm, and each crank arm is coupled to a control arm by a connector link assembly.
When the vehicle is subject to forces which cause it to roll, the crank arms pivot relatively about the longitudinal axis of the rod, against the torsional resistance of the rod. Torsion forces which are exerted through the crank arms urge the control arms of the vehicle back toward their normal position. This type of stabilizer bar acts in a manner such that when paired left and right wheels differ in level from each other due to a cornering maneuver, for example, the vehicle body will be prevented from excessive rolling or leaning to either side by torsional resistance of the stabilizer bar.
The link assembly, which connects the crank arms of the torsion rod to the vehicle body and to the control arms, is generally a bolt-type assembly. Examples of such assemblies are described in, for example, U.S. Pat. Nos. 4,944,523, 5,704,631, 6,402,171, 6,572,127, and U.S. Patent Application No. 2003/0226939; each herein incorporated by reference in their entireties. Generally, in a bolt-type assembly a suitably dimensioned bolt and washer are used to connect the stabilizer bar to the vehicle control arm. Grommets assembled on the bolt engage the exterior surfaces of the stabilizer bar arms and the vehicle control arms. A pair of similarly shaped grommets engage the interior surfaces of the respective vehicle elements and are in engagement with a pair of inner washers which are maintained at a predetermined spaced distance by a cylindrical sleeve mounted on the shaft of the bolt.
Prior art constructions have generally suffered from complexity and cost shortcomings. Such assemblies normally comprises at least four, and sometimes as many as six, different components. Furthermore, assembly is normally done on the vehicle assembly line from these many components.
Limitations with presently available suspension systems include link assemblies that expose the bolt to high levels of stress load during angulation of the control arm and/or stabilizer bar. What are needed are improved grommets that decrease the amount of stress load upon the bolts within suspension systems.